目的 优化设计生物气溶胶监测仪的测量腔结构,增强测量腔结构对样本流的约束能力,从而提高生物气溶胶监测仪的检测精度.方法 根据生物气溶胶监测仪测量腔各部件的结构特点,针对测量腔喷嘴喷口的形状(圆、扁),出口针的长短(22 mm、34 mm),出口流量(1 L/min、2 L/min、2.83 L/min、5 L/min、10 L/min)设计了几组不同部件的参数,并类比流式细胞仪技术中的三维液力聚焦,引入鞘气聚焦结构,设计了四组鞘流与样本流的速度(v样=9m/s,v鞘=3m/s;v样=9m/s,v鞘=4.5m/s;v样=9m/s, v鞘=1.4 m/s;v样=9 m/s,v鞘=0).使用SolidWorks软件对生物气溶胶监测仪测量腔进行设计.基于ANSYS的ICEM与Fluent软件,对测量腔内样本流与鞘流的分布情况进行仿真,对比分析生物气溶胶监测仪在不同情况下腔室内的鞘流与样本流的流动情况与收束段二者的收束情况.结果 在v样=9m/s, v鞘=1.4 m/s,使用圆喷嘴、长出口针,出口流量为2.83 L/min 时,测量腔对样本流的收束效果最好.结论 鞘气结构、喷嘴形状、出口针长短、出口流量大小4种因素均对检测精度有显著性影响,优化后的鞘气聚焦结构能够有效提高生物气溶胶监测仪的检测精度,为该类装置的性能优化提供了理论依据.%Objective The structure of the measuring cavity for the aerosol monitor were optimized to enhance the ability of the structure of the measuring cavity to constrain the sample flow,in order to improve the detection accuracy of the aerosol monitor.Methods According to the structure features of the aerosol monitor,we designed several sets of parameters for different parts:the shapes of the nozzle(round and flat),the length of the export needle(22 mm,34 mm)and the export flow(1 L/min,2 L/min,2.83 L/min,5 L/min,10 L/min). We also used the sheath gas to focus the sample flow,which imitated the three-dimensional hydrodynamic focusing of the flow cytometry technology.We designed several kinds of velocity of sample flow and sheath flow (vsa=9 m/s,vsh=3 m/s;vsa=9 m/s,vsh=4.5 m/s;vsa=9 m/s,vsh=1.4 m/s;vsa=9 m/s,vsh=0).We used the SolidWorks software to design the measuring cavity and used the ICEM and Fluent software to simulate the distribution of the sample flow and the sheath flow.Results The constraint ability of the measuring cavity was the best under this condition:vsa=9 m/s,vsh=1.4 m/s, using round nozzle,long export needle and the export flow was 2.83 L/min.Conclusions The sheath gas structure,the nozzle shape,the length of the export needle and the export flow affect the detection accuracy of the aerosol monitor,and the ability of constraining the sample flow can be enhanced by improving the structure of the measuring cavity.
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